Method of making, supplying and applying chemical treatment to glass fibers

ABSTRACT

A new and improved method for preparing and applying sheer thinning gel to glass fibers wherein the improvement comprises introducing the treatments, after preparation, into closed collapsible containers, controllably advancing the treatments to an application zone, and applying the treatments uniformly to the glass fibers.

United States Patent 2,907,626 10 1959 Eisene tal.

Jerome P. Klink;

Charles R. Morrison, both of Newark, Ohio 773,027

Nov. 4, 1968 Nov. 23, 1971 Owens-Corning Fiberglas Corporation InventorsAppl. No. Filed Patented Assignee METHOD OF MAKING, SUPPLYING ANDAPPLYING CHEMICAL TREATMENT T0 GLASS FIBERS 3 Claims, 3 Drawing Figs.

US. Cl 65/3, 65/l.l W, l l7/l26, 222/92 Int. Cl C03c 25/02 Field ofSearch l 17/126, 126 GR; 222/92, 190, 333; 65/3, I l, I l W; 252/3 15References Cited UNITED STATES PATENTS 3,365,326 1/1968 Conrad 65/3 X3,377,002 4/1968 Weber 222/333 3,414,956 l2/l968 Genson 65/3 3,422,9931/1969 Boehm eta 222/190 3,462,254 8/l969 Marzocchi et al.. 65/33,498,262 3/l970 Hill et al. ll7/l26 X OTHER REFERENCES Starch and ItsDerivatives, 3rd Edition, Vol. II, Radley, pp. 303- 305.

Primary E.\uminer-S. Leon Bashore Assixlum E.\'aminer-Robert L. Lindsay,Jr. Allorrreys-Staelin & Overman and Daniel D. Mast ABSTRACT: A new andimproved method for preparing and applying sheer thinning gel to glassfibers wherein the improvement comprises introducing the treatments,after preparation, into closed collapsible containers, eontrollablyadvancing the treatments to an application zone, and applying thetreatments uniformly to the glass fibcrs.

METHOD OF MAKING, SUPPLYTNG AND APPLYING CHEMICAL TREATMENT T GLASSFIBERS BACKGROUND OF THE INVENTION This invention relates to thepreparation and application of chemical treatments for glass fibers;more specifically it relates to a supply and delivery system of thetreatment so that the latter is protected from contaminants, bacteria,fungi, and oxidation.

In the past, chemical treatments were made up in advance of their beingapplied to glass fibers, but problems inherent with this method werecontamination by dirt and glass particles, destruction by bacteria andfungi, and oxidation of the treatment itself. These contaminants tendedto foul the pumping units used to convey the treatment to applicatorsfor application to glass fibers. Furthermore, when these contaminantsadvanced to the applicators, the latter would be void of the treatment,thereby leaving the glass fibers unprotected. The application efficiencyof the treatment to the glass fiber filaments would then be impairedbecause breakouts" in glass fiber strands would result due to a lack ofthe treatment thereon. A similar situation was presented when thechemical treatment oxidized and small particles therefrom passed throughthe pumping units and advanced to the applicators. Destruction of thetreatment by bacteria or fungi meant that the treatment had to bedisposed of and the pumping system thoroughly cleaned thereby decreasingefficiency. However, if the treatment developed bacteria or fungi afterapplication to glass fibers or fabric, the loss was even greater sincethe latter had to be discarded. When however, a method according to theinventive concept is used, the problems of contamination by dirt andglass particles, destruction by bacteria or fungi and oxidation of thetreatment itself, are substantially eliminated, hereinafter described ingreater detail.

Our chemical treatments are applied to glass fibers as they are beingformed in order to obtain an integral strand that will withstandpostforming operations, e.g. twisting, quilling, weaving, etc. Thechemical treatment comprises a reversible shear-thinning gel compositionwhich is fed to a device comprising a feed supply line, a chamber whichreceives material from the feed line, and a rotating roll which forms anarrow slot with the chamber in order for the roll to obtain a unifonncoating of the treatment. The roll may be optionally driven by a motorto control the rpm. thereof instead of by the glass fibers passing overand in contact therewith. In this manner the roll speed is slower thanthe rate of the fibers being formed so that the latter skid somewhatover the roll and thereby help to supply stress to the reversibleshear-thinning gel.

The instant invention as disclosed and illustrated hereinafter showsimprovements in the application of a coating material or chemicaltreatment to a group of continuous glass filaments or fibers which aresimultaneously produced and then laterally grouped together to form acontinuous glass fiber strand. Continuous glass fiber strands areproduced commercially by maintaining a supply of molten glass in a glassbushing" which has a plurality of minute orifices distributed over thebottom surface thereof. A fine stream of molten glass flows through eachof the orifices, and due to the great increase in surface area of theglass as it is attenuated into fibers, the fibers are cooled to a degreethat chemical treatments can be applied thereto shortly after formation.The many filaments that are formed from a single bushing extend in theshape of a fan to a guide or gathering shoe and proceed to a gatheringroll or forming package in the form of a strand.

In order to insure the application of a chemical treatment (sizes,lubricants, etc.) to each of the glass filaments making up a strand,applicators comprising various designs have been developed and employed.These applicators transfer the chemical treatment to the individualfilaments before they are gathered into a strand or at the point wherethey are gathered into a strand. However, it is preferable to apply thetreatment to the individual filaments before the formation of a strand.

It is desirable and necessary when applying chemical treatments to glassfibers that a uniform coating be applied. Uniformity is desirable andnecessary because of subsequent operations through which the treatedglass fibers or strands are subjected, such as twisting, quilling,weaving, heat-cleaning, dyeing, etc. Without unifon'nity in applicationof sizes to glass fibers, control over the quality of fibers making upfinished products is adversely affected. Uniformity of coating with theinventive concept is much greater than that obtainable heretofore,because of the preciseness and cleanliness by which the treatment isdelivered to the application zone. F urthennore, the use of a precisiongear pump for a uniform, accurate delivery of the treatment at variableflow rates eliminates any pulsations that might cause variations instrand solids. Straining is necessary to eliminate any contaminantssince the tolerances of the pumps are small. A more continuous operationis realized with our inventive concept because all foreign matter iskept out of the treatment from preparation to the time it is applied tothe glass fibers, thereby eliminating fouling of the gear pump.

The improvements in the application of a chemical treatment to glassfibers according to our invention substantially eliminates contaminantsand reduces bacteria and micro-organisrns from entering the treatmentbefore or after application to glass fibers and further preventsoxidation of the treatment before application. Another improvement isthe preciseness by which the treatment, preferably in a gelled form, isfed to the applicator thereby insuring uniformity in coating the glassfibers.

Heretofore when chemical treatments, liquid or gelled, were applied toglass fibers, their manner of delivery to the applicators subjected thetreatments to contamination from the environment, to bacteria and fungi,and to oxidation, all of which adversely affected the quality of thetreated fibers or strands.

It is therefore an object of the present invention to provide apparatusfor preparing, supplying, delivering and applying chemical treatments toglass fibers.

It is a further object of this invention to provide apparatus thathouses and protects chemical treatments for glass fibers fromcontaminants, bacteria, fungi, and oxidation.

It is still another object to provide means for delivery of chemicaltreatments to an applicator with preciseness and free from contaminants.

Other objects and advantages will be apparent from the followingdescription.

SUMMARY OF THE INVENTION It has been discovered that by providing aclosed system for chemical treatments for subsequent application toglass fibers, from the time of straining the treatment after preparationthereof to the time of application to the glass fibers, a high degree ofcoating uniformity is obtained. Uniform coating of glass fibers becomesespecially important in postforming operations such as twisting, plying,beaming, quilling, weaving, dyeing, coronizing, etc., wherein fuzz orbreakouts" appear as defects in the glass yarns or fabrics as a resultof lack of protection of individual filaments from self-abrasion, i.e.,where no chemical treatment has reached particular glass fibers in astrand. Another problem, that arises when there is a nonuniformapplication of the chemical treatment to glass fibers at forming, occursin the heat-cleaning operation of fabrics, wherein streaks may be leftin the fabric because of a heavier buildup of treatment on portionsthereof.

It has always been of major concern to manufacturers of glass fibers tocontrol the amount of chemical treatment or size that is applied toglass fibers in the forming operation while at the same time controllingthe application efficiency Application efficiency as used herein meansthe amount of chemical treatment actually coating the glass fibers ascompared to the amount that is used for coating the fibers. generallyexpressed as a percentage. of the size to the glass fibers. By

gelling the size and depending on the movement of fibers therethroughfor a reversible shear-thinning action to liquify the gelled size,control over application eflicicncy has been realized because there isno loss' of the treatment during application thereof. By controlling therate of delivery of the size to the applicator. such as by metering,preciscness is now realized.

The gel compositions used as chemical treatments for glass fibers have areversible shear-thinning property so that the composition, afterdelivery to an applicator, flows and coats glass fibers passing over andin contact therewith because of a shearing effect created by the fastmoving fibers, and subsequently, almost immediately, the coating on thefibers reverts back to the gel form.

When a delivery system, according to the inventive concept is used tosupply a chemical treatment to an applicating zone for coating glassfibers, a more uniform strand solids, i.e., the amount of chemicaltreatment picked up by the strand, is ob tained. There is consistency inthe solids level of the coating on the strand throughout the formingpackage which comprises a collection of continuously formed strands.

Without this consistency in the solids level of the coated strand,shortcomings in postforming operations appear. For example, in fabricsand weavers products, fuzz, discoloration after heat-cleaning anddiscoloration after dyeing appear, thereby discrediting the quality ofthe product. In reinforcements, when glass fibers do not have a uniformcoating of a sizing thereon, the subsequent wet-out required for highstrength, high quality reinforcement is adversely affected, therebydowngrading the function of the glass fibers as a reinforcement. All ofthe above shortcomings are overcome when glass fibers are treatedaccording to the inventive concept.

By using a reversible shear-thinning gel composition as a sizingmaterial for glass fibers, the application operation is much cleaner andmore efficient since the composition reverts back to its gel state aftercoating the fibers and before being wound onto a forming package.However, the use of a gel composition for glass fibers is not withoutits problems; it must be metered onto an applicator uniformly, the bestknown way being that described herein.

Our delivery system of the gel composition to the applicating zoneprovides a more mechanically reliable system that is easier to handleand that is more flexible than prior delivery systems. Higherapplication efficiencies, less mess and a savings on materials isrealized by our system.

Basically our delivery system comprises a one-way supply and deliverysystem of a chemical material to an application zone wherein glassfilaments, subsequent to forming, are treated so that they may withstandpostforrning operations. After the chemical material has been preparedand put into a closed container, the material may be stored or at anytime drawn out of the container by means of a positive-flow displacementpump.

Because the positive displacement pumps that have been used have verysmall tolerances, contamination of the chemical material from theenvironment, such as dirt or glass particles or oxidized particles fromthe chemical material, must be eliminated in order to insure uniformmetering of the material to the applicators. To obtain a sizing materialfree from contaminants at the applicating zone, it is preferable to usea collapsible container, such as a polyethylene bag where flexibility inthe supply of different sizes to an applicator is required. However,where this flexibility is not required a closed container such as astainless steel vessel is adequate.

in our system, as the bag is filled, air vents therefrom, so that whenthe bag is filled substantially less than 1.0 percent by volume of airremains in the bag. A close analogy is that of a balloon filled with aliquid except that polyethylene does not stretch like a balloon. Afterthe bags are filled they must be transported to a storage area or to thepumping area. This is done by using a carriage into which the bag isfitted before filling. To reduce stresses set up in the bag because ofit being filled, the bag must be large enough to be in excess of theconfines of the carriage. The bag is equipped with a fitting on thebottom thereof, which passes through the bottom of the carriage, toallow the material therein to be withdrawn. The fitting consists of aflanged nipple adaptable to receive a flexible tubing so that the lattercan be attached to a manifold line which supplies an unlimited number ofpumps, depending upon the rate of supply to and the rate of withdrawalfrom the manifold.

The only piping system required for our gelled chemical treatment isfrom the pumps to the applicators, whereas when liquid treatments wereused a more complex piping system was required. Heretofore when adifferent sizing material was desired on different applicators alignedin a bank or row, a separate piping system was required, which involvedseparate overflow tanks and return lines. However, when gel sizes aredelivered to the applicators via our method, the piping is much simplerand no overflow tanks and no return lines are required.

Heretofore, when the chemical material to be used as a sizing for glassfilaments was in a liquid form, bacterial contamination of the materialwas a major problem. If bacteria invaded the material before applicationto glass fibers, the material had to be discarded. Conversely, if thematerial became inflicted with bacteria after application thereof toglass fibers, it rendered the latter unusable. This problem is greatlyreduced and substantially eliminated when a supply and delivery systemaccording to our concepts is used. Since the chemical material is in gelform, a positive displacement pump can be employed. When the material isin liquid form, this is not feasible since return lines are required toreturn overflow of material in the applicating zone back to the pumpingstation. Recycling of liquid treating material exposes the overflow andthe unpumped material to possible contamination.

However, when the chemical material is in gel form, the bacteria canfeed not only on the starch but also on the gelling agent. Therefore, itis imperative that a completely closed system be used from the time ofpreparation of the material to the time of delivery to the applicatingzone in order to reduce formation of bacteria. After the glass filamentsare sized with the chemical treatment, they are gathered into a strandand wound onto a package. The package is dried at a temperature greaterthan the boiling point of water, preferably at about 230 F. to 265 F. todrive out the water and to prevent bacterial growth on the sizedpackage. When the package is not dried, but is used within a short timein a twisting or plying operation, water is driven off the strand as itis whipped about by the apparatus at high speeds and at roomtemperature.

Although it is not necessary to use a collapsible container in order forour method to be practiced, it is preferable where a high degree offlexibility is required in supplying various chemical treatments atdifferent times to the pumping station. Otherwise, an enclosed,noncollapsible container is sufficient.

it is one theory that when bacteria attacks a sizing material containingstarch, the latter is converted to a sugar, which.

changes the intended properties of the sizing material so that the glassfiber strand is not protected, thereby leading to fuzz. Furthermore,when glass fibers, subjected to bacterial attack, are heat-cleaned,streaking in glass fabric results. It is known that when sugar isburned, carbon is formed, and if sugar is on the fabric it is extremelydifficult to burn off.

Sometimes on a glass fiber fabric which has been inflicted with bacteriaor fungi, areas of difierent colors such as reds, blues, browns, appearor spotting occurs; this is also thought to be caused by a conversion ofstarch to sugar.

The bacteria and/or fungi problem that arises when starch sizes are usedis not new to the art. Antifungi agents such as tri-butyl tin oxide havebeen used in the past, but bacteria and fungi have now become partiallyimmune to these agents. Heat, over F., has also been applied to thesizing materials to destroy bacteria and fungi but some sizes have to beapplied at room temperature.

With liquid sizes, such as used in the art, a closed system could not beused, since the application efficiency of the size to the fibers is verylow, thereby requiring an overflow tank and return line. Preciseness inthe delivery of a liquid size is not possible and furthermore, the. sizepicks up contaminants from the atmosphere and thereby exposes the supplythereto.

An auxiliary feature of using our supply and delivery system is that airin the form of bubbles is kept out of the system which means that theapplicators will not develop bubbles. This is important since bubblesbreak when a glass filament comes in contact therewith, to create anuneven film or void on the applicator, thereby leaving some filamentssubstantially void of any size along a substantial length of continuousstrand.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view, partly incross section, which shows the making of a chemical treatment, thestoring of the treatment in a collapsible container, transporting thetreatment to a pumping station, pumping of the treatment to an application zone, applying the treatment to glass fibers as they arefonned and winding the treated fibers onto a package.

FIG. 2 is a fragmentary, enlarged view of a pumping station used todeliver chemical treatments to an applicating zone.

FIG. 3 is a fragmentary, enlarged cross-sectional view of a collapsiblecontainer supported in a carriage, which houses a chemical treatment tobe used on glass fibers.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The nature of the presentinvention will be more fully understood from the following descriptionwherein reference is made to the drawings. i

Constituents that make up a chemical treatment I for application toglass fibers are mixed in a vessel 2 as shown in FIG. I, which isequipped with a water jacket 3 so that the temperature of the contentswithin the tank 2 may be raised, lowered or maintained as desired. Thetank is also equipped with a high speed mixer 4. For some chemicaltreatments I a high shear device 6, e.g., a homogenizer, is required toreduce the particle size of the treatments I and also to homogenize thetreatments. When the high shear device 6 is used, cutoff valve 8 isclosed and valve 10 is opened to allow the treatment I in the vessel 2to pass through the high shear device 6. A return line 13, from the highshear device 6 to the vessel 2 is provided so that multiple passes ofthe treatment 1 may be made therethrough. Load-out hoses l5, areprovided after and adjoining valves 8 and 14. The load-out hose I5 isequipped with a strainer 16 having 40-100 mesh screen.

When the chemical treatment I is thoroughly mixed, it is passed throughstrainer 16 and into a collapsible container 18, preferably apolyethylene bag, which is housed in a metal castered box 20. The metalcastered box 20 has a small opening in its bottom surface to allow aflexible tubing 22 that is connected to the container 18, to be passedtherethrough. When the collapsible container 18 is completely full it isfitted with a snap-on cap 23 so that the treatment 1 therein isprotected from contaminants, oxidation and bacteria. From this point intime the chemical treatment 1 is not exposed to the elements until it issubsequently applied to glass fibers.

The metal castered box 20 is transported to a pumping station which isused to deliver the chemical treatment I to an applicating zone. Thepumping station comprises a manifold 26 which is supplied by controllingthe flow of the treatment from the collapsible container 18 with asupply valve 24. There is no limit as to the number of supply valvesthat may be attached to the manifold 26 from other containers 18, butrather is dependent upon the number of positive displacement pumps 28,and the rate of flow of the treatment 1 to the applicating zone.

Flexible tubing 30 is fitted to each pump 28 so that the treatment I isdelivered to an applicator device 32. The applicator device 32 comprisesan opening for entry of the treatment 1, preferably in gelled form, anda chamber to receive the treatment. An applicator roll 38 is mountedwithin the device 32 so that two narrow slots are formed between theroll 38 and the chamber containing the treatment, wherein the slotsextend along the length of the roll. By the action of the roll, which isrotating by means of a motor or as a result of a fan of glass fibers 36being formed from a precious metal bushing 34 containing molten glass,and passing in contact with roll 38, the gelled treatment 1 momentarilybecomes a liquid and coats the applicator roll 38 with a unifon'n filmof the treatment. As long as the roll 38 is rotating, the treatment I onthe roll 38 remains a liquid as does that part of the treatment i in thechamber of the applicator device 32 that actually contacts the rotatingroll 38. However, when the roll 38 is not rotating the treatment 1coating the roll 38 reverts back to the gel form until the glass fibers,through a shearing action, transform the gel again to a liquid to coatthe fibers with a uniform film. Again, the treatment reverts back to thegel form just after application to the glass fibers. The individuallycoated glass fibers are collected into a strand 41, by means of agrooved graphite wheel 39, and wound onto a forming package 40, by meansof a traversing device 42, such as spiral wire traverse. The package 40is then ready for postforming operations or for drying so that it can bestored without fear of picking up any bacteria from the environment.

In an enlarged view of the pumping station, FIG. 2 shows the manifold 50with supply valves 52, 52 regulating the flow of the chemical treatment51 so that the positive displacement pumps 54 can draw the treatment 51through flexible tubing 55 attached to the manifold 50 and forward itthrough additional flexible tubing 56 to the applicating zone.

FIG. 3 shows a collapsible container 60 substantially filled with achemical treatment 63, securely sealed with a cap 62, wherein thecontainer occupies substantially the internal confines of the metal box61 (the casters for the box are not shown). A hollow flanged nipple 64is fitted on the container 60 so that the nipple 64 protrudes throughthe container and is seated on an oversized nylon washer 66, which helpsto prevent abrasion of the container at the opening of the metal box 61.Flexible tubing 68 is then fitted over the nipple 64 so that thechemical treatment 63 can be advanced to the manifold, the latter notbeing shown.

The size of the collapsible container 60 must be adjusted so thatstresses therein, which are set up on transporting the castered metalbox 61, do not rupture the container 60.

Although a specific method has been disclosed, it is to be understoodthat variations and modifications can be made within the spirit andscope of the invention.

We claim:

1. In a method of preparing and handling an reversible shear-thinninggel composition for application to glass fibers, comprising the stepsof:

a. adding constituents to a vessel to form the composition;

b. mixing the constituents with a high shear device to reduce particlesize and to ensure a homogeneous composition;

c. applying the homogeneous composition to a plurality of advancingindividual glass filaments so that the linear movement of the filamentsmoving in a cooperating relationship with the composition momentarilyconverts the composition into a liquid which coats the filamentsuniformly and then immediately thereafter reverts back to a gel on thefilaments;

d. gathering the glass filaments with the composition thereon into amultifilament strand;

e. collecting the multifilament strand on a package; and

f. drying the package to drive out water therefrom and to preventbacterial growth thereon;

the improvement comprising:

g. straining the homogenous composition into a collapsible container sothat when filled, the container is substantially free of air;

h. sealing the filled collapsible container so that the homogeneouscomposition may be withdrawn therefrom at a subsequent time withoutcontamination by dirt, bacteria or oxidation;

i. conveying the sealed container to a pumping station equipped with areceiving manifold and a plurality of positive displacement pumps;

j. supplying the manifold with sufiicient homogeneous composition fromthe sealed container without having to expose the composition to theatmosphere; and

k. pumping the homogeneous composition from the manifold to anapplicating zone via one-way positive flow,

wherein the composition is in a closed system from the straining step(g) through the pumping step (k).

2. The method as claimed in claim 1 wherein the delivery of thecomposition to the applicating zone for application of the compositionto the glass filaments is precisely controlled so that the compositionsolids are uniform throughout the length of the glass filaments.

3. A method of providing flexibility and a high degree of preciseness ina closed system delivery of a reversible-shearthinning gel compositionused to size glass fibers, comprising the steps of:

a. introducing the composition through a strainer into a collapsiblecontainer until the container is full and void of air, said containerhaving a tubing and a control valve thereon, to allow the composition tobe subsequently withdrawn therefrom;

b. closing the container so that the composition is protected from thecontaminates, oxidation, and bacteria;

c. advancing the closed container to a central pumping stationcomprising a manifold and a plurality of positive displacement pumps;

d. supplying the manifold with sufficient composition from the closedcontainer by controlling the valves on the tubing wherein thecomposition is not exposed to the elements; and

e. controllably pumping the composition from the manifold via saidpositive displacement pumps to an applicating zone, wherein glass fibersupon formation come into contact with an applicator that applies thecomposition uniformly to the fibers;

so that as the composition is first exposed to the atmosphere via theapplicator as in step (e) it is consumed substantially immediately bythe advancing glass fibers.

I I I! t

2. The method as claimed in claim 1 wherein the delivery of thecomposition to the applicating zone for application of the compositionto the glass filaments is precisely controlled so that the compositionsolids are uniform throughout the length of the glass filaments.
 3. Amethod of providing flexibility and a high degree of preciseness in aclosed system delivery of a reversible-shear-thinning gel compositionused to size glass fibers, comprising the steps of: a. introducing thecomposition through a strainer into a collapsible container until thecontainer is full and void of air, said container having a tubing and acontrol valve thereon, to allow the composition to be subsequentlywithdrawn therefrom; b. closing the container so that the composition isprotected from the contaminates, oxidation, and bacteria; c. advancingthe closed container to a central pumping station comprising a manifoldand a plurality of positive displacement pumps; d. supplying themanifold with sufficient composition from the closed container bycontrolling the valves on the tubing wherein the composition is notexposed to the elements; and e. controllably pumping the compositionfrom the manifold Via said positive displacement pumps to an applicatingzone, wherein glass fibers upon formation come into contact with anapplicator that applies the composition uniformly to the fibers; so thatas the composition is first exposed to the atmosphere via the applicatoras in step (e) it is consumed substantially immediately by the advancingglass fibers.